Device for transferring heat between a panel heated by solar radiation and a wall

ABSTRACT

A device for transferring heat between a panel heated by solar radiation and a wall surface, including an insulating plate mounted parallel between the panel and the wall surface, to define a closed external space between the panel and the insulating plate, and a closed internal space between the insulating plate and the wall. An air circulator is interposed between the external space and the internal space and can be put selectively in an open state allowing circulation of air between the external space and the internal space, and thus allowing thermal transfer between the panel and the wall, and a closed state preventing circulation of air between the external space and the internal space, and thus preventing thermal transfer between the panel and the wall.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a device for transferring heat between a paneldesigned to be heated by solar radiation and a wall, such as for examplethe wall of a building.

2. Description of the Related Art

There are already known arrangements applied to the face of a buildingfor capturing solar energy and heating a receiving medium such as, forexample, an outside wall of the building or a volume of air inside thebuilding.

These arrangements for capturing solar energy are sometimes also called“solar panels” or “transparent insulation”.

An arrangement of this type is described for example in French PatentNo. 92 03962.

This known device comprises a number of substantially horizontal shapedelements spaced apart and superposed to form a curtain having anexternal face designed to be exposed to solar radiation and an internalface designed to be arranged facing the receiving medium which is to beheated. This device thus permits the transfer of the heat while at thesame time constituting an efficient insulation.

In such a device there is normally provided a conversion plate whichforms part of the panel and which ensures the conversion of the solarenergy into heat.

The transfer devices of the solar panel type are generally applieddirectly to the face of the building to allow not only a transfer ofheat derived from the solar radiation collected, but also a thermalinsulation when the solar radiation is absent.

SUMMARY OF THE INVENTION

The invention takes as its starting point an appreciation of the factthat the solar panels known at present are not able to deal with all thesituations which are encountered in practice.

The applicants have come to appreciate that in fact four differentsituations exist and need to be dealt with:

a) the heat provided by the solar radiation is welcome and it needs tobe transferred to the surface, for example a wall, to be heated.

b) an excess of solar heat is present and it is therefore necessary toavoid any transfer of heat between the panel and the surface to beheated.

c) there is no solar heat available and it is necessary it to avoid anyloss of heat from the surface, for example the wall, towards theoutside.

d) there is no incoming solar heat present but there is an excess ofheat present in the surface. It is therefore necessary, to the extentpossible, to reject this heat to atmosphere.

The principal aim of the invention is to provide a heat transfer deviceof the type defined in the introduction which is capable of handling inpriority the first three situations (a, b, c).The fourth situation (d:cooling at night) demands in principle a supplementary logic and thehandling of this situation is only really needed in certain climates.

The device according to the invention comprises, for this purpose, aninsulating plate designed to be mounted between the panel and the wallsurface, parallel to these, in such a way as to define a closed externalspace between the panel and the insulating plate and a closed internalspace between the insulating plate and the wall, as well as aircirculating means interposed between the external space and the internalspace and capable of being put selectively in at least one of thefollowing states:

an open state allowing circulation of air between the external space andthe internal space and thus allowing thermal transfer between the paneland the wall;

a closed state preventing circulation of air between the external spaceand the internal space and thus preventing thermal transfer between thepanel and the wall.

Thus, depending on the state (open or closed) of the air circulatingmeans, it is possible to cause or on the contrary to prevent a transferof heat between the panel and the wall. When the air circulating meansare in an open state, a transfer of heat takes place between the paneland the wall. By contrast, when the air circulating means are in theclosed state, there is no transfer of heat but on the contrary a goodthermal insulation.

The invention thus achieves mastery over the transfer of heat byconvection while preventing the direct conductive and/or radiativecontact between the panel and the wall by interposing a particulardevice. This device, with its two empty spaces and its insulating platebetween the panel and the wall, guarantees low conduction of heat aswell as low transfer by radiation, while allowing the transfer of heatby convection.

The panel to which the invention is applied could be in any position:vertical, inclined or horizontal.

In principle the wall surface to which the heat is to be transferred isa masonry wall, but it could also take the form of a flat roof or even avessel containing a liquid.

In one preferred embodiment of the invention the air circulating meanscomprise at least two openings provided in the insulating plate and eachdesigned to provide communication between the external and internalspace.

In practice it has been found that a single opening allows only verylimited exchange of air.

The term “opening” such as is used here is intended to designategenerally any passage, possibly including restrictions or bends,providing communication between the internal and external spaces of thedevice.

Preferably the air circulating means comprise two openings positionedsubstantially at the same height with respect to one wall of the devicesuch as to allow limitation of the flow of air passing from one openingto another. By contrast, if the openings are not at the same height itis necessary to be able to block the natural flow of air, for example bymeans of a flap valve.

Preferably a partition or dividing wall is arranged in each of theexternal space and the internal space to define, in each of the saidspaces, at least one path for circulation of generally U shape havingtwo branches, one on each side of the partition.

This arrangement of U-shaped circuits consists essentially of verticalwalls. It ensures good scouring of the surfaces and facilitates thecirculation of the air in each of the external and internal spaces, aswell as a circulation of the air from one to the other. An effectanalogous to scouring could be obtained by other means, for example bybends or diversions, or even by other types of circuit for circulatingair between the two above-mentioned spaces.

Preferably the said air circulating means comprise at least one firstopening providing communication between a first branch of the externalspace and a first branch of the internal space, and at least one secondopening providing communication between a second branch of the externalspace and a second branch of the internal space.

According to another feature of the invention the air circulating meanscomprise at least two openings extending through the insulating plateand of which at least one is provided with a flow regulating memberdesigned to adopt one or the other of the open and closed conditions.

In one embodiment of the invention the control member comprises anelectric or similar fan designed to be put into operation or out ofoperation corresponding respectively to the open condition and theclosed condition.

Thus, when the fan is in operation a circulation of the air is obtainedsimultaneously in each of the external and internal spaces and from onespace to the other. By contrast, when the fan is out of action thecirculation of air is stopped.

In another embodiment the control member comprises an electric fan and aflap valve which is situated in the same opening as the electric fanand/or in another opening.

Preferably use is made of a gravity-operated flap which opens under thepressure of the air and closes under gravity. This valve is closed bygravity when the fan is not providing the pressure necessary to open it.When the fan and the valve are placed in two different openings, theselatter are not necessarily at the same height. This valve could even beomitted if the two openings are situated at the same height, preferablyhigh up or low down.

When the device is to used on a flat roof it is preferable to provide,in addition to the fan, a flap valve in each opening.

In place of a gravity-operated valve it is possible also to make use ofa flap operated by a bimetal strip heated by the solar radiation or anelectro-magnetically controlled flap. In certain versions one could evenaccept having a flap controlled manually by mechanical means.

When insolation is present and the transfer of heat to the wall surfaceis closed off, the temperature could attain levels which, for certainmaterials, in particular insulation, are excessive.

With this in mind, the invention provides means for protection againstthe occurrence of excessive temperatures.

One measure for this purpose consists in positioning a supplementaryplate, which we call a stopper plate, between the panel and theinsulating plate in order to create a closed blocking space between theexternal space and the insulating plate. If necessary this blockingspace could be ventilated, preferably by a flow of atmospheric airthrough a fixed opening low down and another opening with- a valvehigher up. This valve could be operated by a bimetallic strip when thetemperature reaches a certain predetermined threshold. Should theoccasion arise, the excess heat is removed to atmosphere.

Another step consists in placing an intermediate plate, which we call aconversion plate, between the panel and the insulating plate to create afirst air circuit (or heating circuit) designed to transfer the heatbetween the intermediate plate and the wall surface or vice versa, andto create a second air circuit (or cooling circuit) designed to rejectthe heat to the outside. Equally it is provided that the first aircircuit and the second air circuit have respectively first aircirculating means and second air circulating means which are capable ofbeing placed selectively and independently of one another in an opencondition or a closed condition.

The conversion plate transforms the solar energy into heat and it thenreplaces that which normally comprises the panel.

The first circuit allows the transfer of the heat from the conversionplate to the wall surface or vice versa, depending on whether one is ina winter or a summer regime. The second circuit is designed to rejectthe heat to the outside: to evacuate the heat from the wall surface tothe outside and/or extract the excess heat from the intermediate plateto the outside.

Preferably the first air circuit is a closed circuit capable ofcommunicating with the outside through a small pressure-equalisingopening, whereas the second air circuit is a closed circuit or is opento the outside.

By the expressions “closed circuit” and “open circuit” it is intended tomake clear that the circulation of the air takes place in one or severalspaces or volumes, respectively without communication with the outsideand with communication with the outside.

The device of the invention furthermore includes control means designedto control the flow regulating member, for example the fan.

In one embodiment of the invention these control means comprise manualcontrol means.

In another embodiment these control means comprises at least twotemperature sensors designed to detect the temperatures respectively ofthe panel (or of a conversion plate) and of the wall surface, and tocontrol the flow regulating member as a function of the difference intemperature between the panel (or conversion plate) and the wallsurface.

In one embodiment which has been developed, these control means compriseelectronic means.

Preferably the control means comprises at least one photo-responsivecomponent designed to detect the insolation on a panel and to generatean electrical voltage representative of the insolation.

The photo-responsive component could be a photo-voltaic cell which willallow the generation of energy which can be used directly to drive thefan. However one could also make use of photo-transistors, photo-diodesor photo-resistances which provide a signal which can be used directly(through the intermediary of an amplifier) to operate the fan, orindirectly as data for a calculation by a logic circuit.

By way of example, one could make use of a photo-transistor coupled to a“Darlington” type of circuit which delivers an output power sufficientto drive a fan operating on a direct voltage of 12 volts.

The electrical voltage thus generated could be used either directly asenergy for driving the flow regulating member or in the form of a signalfor initiating or halting the operation of the flow regulating member.

In place of a photo-responsive component it is possible to envisagemaking use of at least one thermo-sensing component, for example adetector of the temperature or of the difference in temperature, athermostat or a bimetallic strip.

The device according to the invention is preferably in the form of amodule of standard or specific dimensions having a frame which supportsthe components of the device.

BRIEF DESCRIPTION OF THE DRAWINGS

In the description which follows and which is provided solely by way ofexample, reference is made to the accompanying drawings in which:

FIG. 1 is a partly sectioned view of a transfer device according to theinvention placed between a panel designed to be heated by solarradiation and a wall surface to be heated;

FIG. 2 is an elevation of a transfer device according to the inventionin the form of a modular element;

FIG. 3 is a section on the line III—III in FIG. 2;

FIGS. 4, 5 and 6 are views analogous to FIG. 1 and showing othervariants;

FIGS. 7 and 8 are elevations analogous to FIG. 2 and showing othervariants;

FIG. 9 is a partly sectioned view of a device according to the inventionincluding a blocking space;

FIG. 10 is an elevation of a transfer device showing another embodimentof the invention;

FIG. 11 is a section on the line XI—XI in FIG. 10;

FIG. 12 is a section on the line XII—XII in FIG. 10;

FIG. 13 is a section through a transfer device with two air circuitsaccording to the invention; and

FIG. 14 is a section analogous to FIG. 13 showing a variant.

DESCRIPTION OF THE EMBODIMENTS

We refer first to FIG. 1 which shows a heat transfer device 10 accordingto the invention, mounted between a panel 12 designed to be heated bysolar radiation S and a wall surface 14 which constitutes the wall of abuilding. The panel 12, also known as a “solar panel” or “transparentinsulation” is, in this example, realized in accordance with theteaching of French Patent No. 92 03962. It will be understood that thispanel could take another form, of a kind, which allows the capture ofsolar energy.

In the example the panel 12 comprises a number of substantiallyhorizontal identically-shaped elements 16 spaced from one another, andsuperposed in a substantially vertical plane to form a kind of curtain.This curtain has an external face 18 and an internal face 20. Theexternal face 18 is closed by a transparent plate 19 (for example asheet of glass) designed to be exposed to solar radiation S. Theinternal face 20 is closed by a plate 22 such as a metal sheet coloredblack.

The plate 22 constitutes a conversion plate which transforms the solarenergy into heat. It could be separate from the panel 12, as will beseen later.

The shaped elements 16 allow the conduction of solar energy from theexternal face of the curtain to the internal face, that is to saytowards the metal plate 22. Furthermore these shaped elements definebetween them rising channels which create a number of warm cushions ofair. These cushions of air are held immobile and constitute at the sametime a very good insulator with a reduced coefficient of thermal loss.

The wall surface 14, which constitutes the wall of a building, has anexternal face 24 facing towards the device 10 and an internal face 26facing towards the interior I of the building.

The transfer device 10 comprises essentially an insulating plate 28designed to be mounted between the panel 12 and the wall 14, in adisposition substantially parallel to the latter. This insulating plate28 is spaced away from the panel 12 and wall surface 14 in such a way asto define on the one hand an external closed space 30 between the paneland the insulating plate and on the other hand an internal closed space32 between the insulating plate and the wall surface.

We now refer to FIGS. 2 and 3 to describe in detail the structure of thetransfer device 10. This device is realized in the form of a modularelement of generally rectangular shape (FIG. 2) capable of havingstandard dimensions or dimensions adapted to need.

The insulating plate 28 is supported by a frame 34 having, in verticalsection, the shape of an angle-iron having a limb 36 surrounding theperiphery of the insulating plate 28 and a limb 38 designed to beapplied against the external face 24 of the wall 14 (FIG. 3).

This plate 28 is made of a thermally insulating material such as a foamof plastics material, of minerals fibers, etc. The insulating plate 28has a face 40 designed to be applied against the limb 38 of the frameand an opposing face 42. It has a thickness E which could for example bebetween 1 and 10 centimeters.

The frame 34 has a lower face 34-1, an upper face 34-2 and two verticalsides 34-3 and 34-4.

The device 10 furthermore has two substantially vertical partitions,namely a partition 44 arranged along the face 40 of the insulating plate28 and a vertical partition 46 arranged along the face 42 of theinsulating plate 28 (FIG. 3).

Each of these partitions extends away from the lower face 34-1 of theframe and terminates at a distance D from the upper face 34-2 of theframe (FIG. 2). The partitions 44 and 46 are of substantially the sameheight. The result is that the external space 30 and the internal space32 have a generally U-shaped configuration.

The insulating plate 28 has a series of first openings 48 passingthrough the plate at intervals and aligned on a horizontal line situatedat a height h1 with respect to the lower wall 34-1 of the frame. Theseopenings 48 provide communication between a first branch 30-A of theexternal space 30 and a first branch 32-A of the internal space 32 (FIG.3).

In addition, the insulating plate 28 is provided with a second opening50 situated at a level h2 with respect to the lower wall 34-1 of theframe (FIG. 2) and providing communication between a second branch 30-Bof the external space 30 and a second branch 32-B of the internal space32.

Thanks to the partitions 44 and 46, to the opening 48 and to the opening50, the air can circulate in a circulation path F of generally U shape,simultaneously in the external space 30 and the internal space 32.

In accordance with the invention, the device has a fan 52 (FIGS. 1, 2and 3) which is mounted in the circular opening 50. This fan has acasing 54 designed to be located in the opening 50 and carrying anelectric motor 56 serving to drive a fan rotor 58.

This fan 52 thus provides mechanical ventilation regulating the amountof air circulating in each of the spaces 30 and 32 and between thelatter. The fan can be set either in an open state (operation) or in aclosed state (stop).

When the fan is in operation it causes a circulation of air between thespaces 30 and 32 and thus allows a transfer of heat between the panel 12and the wall surface 14.

By contrast, when the fan is stopped, it prevents the circulation of airbetween the spaces 30 and 32 and thus prevents a transfer of heatbetween the panel 12 and the wall surface 14.

In the embodiment of FIG. 1 the fan 52 has a manual control 60 situatedin the interior I of the building and connected to the fan through anelectric cable 62 (FIGS. 1 and 3).

In the embodiment of FIG. 4 the control means for the fan comprise twotemperature sensors 63 and 64 designed to detect the temperatures of thepanel 12 (plate 22) and of the wall surface 14 respectively. Thesesensors 63 and 64 are connected to a differential thermostat 66 designedto control the fan 52 in response to the difference in temperaturebetween the panel and the wall surface. The result in that control ofthe fan is achieved automatically.

This automatic control can be sophisticated to a greater or lesserdegree and can incorporate, for example, electronic control means totake account of the principal parameters involved and thus to optimizethe transfer of heat as a function of the thermal conditions and of therequirements.

In the embodiment of FIG. 5, the control means include at least onephoto-voltaic cell 68 carried by the panel 12 and designed to detect theinsolation on a panel and to generate an electrical voltage Vrepresentative of the insolation. In the case of FIG. 5, this electricalvoltage is used directly as the energy for driving the electric motor ofthe fan 52.

In the embodiment of FIG. 6, the control means likewise include at leastone photo-voltaic cell 68. However it is utilized in this case toprovide a signal S to a unit 70 for initiating or halting the operationof the fan 52.

Each of the modular elements, which could have a horizontal extent offor example between 1 and 2 meters and have a vertical height of forexample between 1.50 and 2 meters, constitutes an independent moduleequipped with its own fan.

According to the invention the control of the fans could be global, thefans being thus liked in parallel or on the contrary individually, eachfan responding to its own command. Individual control could be of theinterest because it makes it possible in particular to take account ofthe shade projected on to the face of the building by trees orneighboring houses.

In the case where the device has sophisticated control means theselatter take account simultaneously of the temperature of the panel 12and that of the wall surface 14, as well as the external and internaltemperatures. These control means incorporate instructions and criteriain addition.

The panel 10, also known as transparent insulation, could berudimentary, given that the device 12 according to the invention is themain contribution to the transfer of heat.

Thus this device 10 is not necessarily limited to a device as describedin French Patent 92 03962 referred to above.

By way of example the device 10 could include a glazed facade (glass,polycarbonate, etc) constituting the external face 18, an empty spacewith vents for example, films or non-woven transparent materialsprovided for restricting the movement of air; and a black sheet toconstitute the plate 22.

In the embodiment of FIG. 7 the device is like that of FIGS. 1 and 3 andcould include or not include a double U-shaped circulation arrangement.It has an opening 50 provided with an electric fan 52 and an opening 48provided with a gravity-operated flap valve 72. In the example the fanand the valve are situated in different openings placed at the levels h1and h2 which could be the same or different. In a variant they could beplaced in the same opening.

In embodiment of FIG. 8 the device is comparable with that of FIGS. 1and 3 and could include or not include a double U-shaped circulationarrangement. It has an opening 50 provided with an electric fan 52 andopenings 48 each provided with a gravity-operated flap valve 72.

The device according to FIG. 9 has a supplementary plate 74, a “stopperplate”, realized for example in the form of a sheet of aluminium andplaced between the panel 12 and the insulating plate 28 in such a way asto allow the creation of a closed blocking space 76 between the externalspace 30 and the insulating plate 28. Where appropriate, this blockingspace could be ventilated, preferably by a natural current of airthrough a fixed opening 78 at the bottom and an opening 80 provided witha valve 82 higher up. The openings 78 and 80 provide communicationbetween the blocking space 76 and the external ambient air through thepanel 12. The valve 82 is operated by a bimetallic strip 84 when thetemperature reaches a certain threshold. This strip is placed into theexternal space 30 behind the panel 12.

In the embodiment of FIGS. 10 to 12 the device is a module having aframe 34 supporting an insulating plate 28. This plate 28 is providedrespectively at the top and the bottom with two openings 86 and 88 ofrectangular shape extending horizontally to provide communicationbetween the external space 30 and the internal space 32.

The insulating plate 28 is also provided with a central opening 90 ofcircular shape in which is mounted an electric fan 52 and two lateralopenings 92 of oblong shape arranged one on each side of the centralopening 90 on a horizontal line.

Furthermore of the external space 30 is divided by a substantiallyhorizontal partition 94 into two superposed compartments 30A and 30B,whereas the internal space 32 is divided by a substantially horizontalpartition 96 into two superposed compartments 32A and 32B.

The result is that a flow of air can circulate from one space to theother under the action of the fan 52, following the path indicated bythe arrows. The flow of air passes from the compartment 30B to thecompartment 32A through the opening 90, then reaches the compartment 30Athrough the opening 86. After this the flow of air reaches thecompartment 32B through the openings 92 and then returns to thecompartment 30B through the opening 88, and so on.

In the embodiment of FIG. 13, the device is similar to that of FIG. 9.It has an intermediate plate 98 which is positioned between the panel 12and the insulating plate 28. This intermediate plate, also called aconversion plate, allows the solar energy to be converted into heat. Itgenerally takes the form of a solid body, preferably black in color.

The result is that the plate 22 formed of a black metal sheet (FIG. 1)could be replaced by the panel 12, and then the conversion of the solarenergy into heat is achieved in this case by the intermediate plate.

This allows the creation of three spaces: a space 100 between the panel12 and the conversion plate 98, a space 102 between the plate 98 and theinsulating plate 28, and a space 104 between this insulating plate andthe wall surface 14.

The spaces 102 and 104 allow the creation of a first air circuit,indicated by the arrows 106, under the action of the first aircirculating means constituted here by a fan 52 analogous to thatdescribed as earlier. This fan 52 is provided in the lower part of theinsulating plate 28. This first air circuit communicates with theoutside atmosphere through a small pressure-balancing opening 108.

Furthermore the space 100 communicates with the atmosphere through twoopenings 110, 112, respectively in the upper region and in the lowerregion. This allows the creation of the second air circuit indicated bythe arrows 114, under the action of a fan 116 positioned in the lowerregion of the space 100.

The first circuit 106 is in principle a closed circuit whichcommunicates with the outside solely through the pressure-balancingopening 108. Here the second circuit 114 is open to the outside but in avariant it could be closed.

The first circuit constitutes a heating circuit designed to transfer theheat from the conversion plate 98 to the wall surface 14, and viceversa, according to whether one is in a winter or summer regime. In factthis first circuit corresponds to the different circuits describedearlier.

The second circuit constitutes a cooling circuit which is designed toreject the heat to the outside. It could remove the heat from the wallsurface 14 to the outside (for example at night in summer) and/or removethe excess heat from the conversion plate 98 to the outside (for exampleon a sunny day in summer).

The first air circulating means 52 and the second air circulating means116 can be placed selectively and independently in an open state or aclosed state, thus defining altogether four possible operating states.

These two circuits are open to numerous variations, one of which isillustrated in FIG. 14. In this version the first circuit 106 followsthe spaces 100 and 104, while the second circuit 114 uses the space 102.

In a variant, these two circuits could have part of their path in commonand comprise air circulating means with fans and valves operating asspurs to the achievement of either heating or cooling.

In another variant the second circuit could be confined to a singlespace. In that case a fan placed in this space causes turbulence and, asa consequence, a good convection between walls. Moreover with the fanstopped, this space then acts as an insulator.

It will be understood that the invention is not limited to theembodiments described above by way of example, and extends to othervariants.

It will be appreciated that the conversion of the solar energy into heatis achieved on a solid body, preferably black, which could be a plate(in principle a sheet) placed against the transparent insulation (plate22 in FIG. 1) or equally well against the insulating wall 28, or evenmidway between the transparent insulation and the insulating wall 28(intermediate plate 98 of FIGS. 13 and 14).

Instead of a plate one could make use of an opaque surface which couldfor example be situated on the back face of a glazed area. One couldeven make use of a network or grid, for example a mineral or metallicwool which is permeable to air.

In the examples described above the shaped elements 16 of the panel 12(see FIG. 1) define rising channels. However it is also possible toenvisage inclining them in the opposite sense to create channelsdescending from outside to inside.

Furthermore, when the device is realized in the form of a module itcould be arranged that the frame supports the assembly of components ofthe device including the panel.

The device according to the invention thus allows complete mastery ofthe four situations listed above and allows the initiation or preventionof the transfer of heat as a function of the conditions which areencountered and of the instructions of the user.

What is claimed is:
 1. Device for transferring heat between a panel to be heated by solar radiation and a wall, the device comprising: an insulating plate mounted parallel between the panel and the wall to define an external closed space between the panel and the insulating plate, and an internal closed space between the insulating plate and the wall; a partition mounted in each of the external space and the internal space to define therein at least one U-shaped path with two branches for air circulation, one branch on each side of the partition; an air circulator interposed between the external space and the internal space, wherein said air circulator includes at least two openings provided in the insulating plate, each of which is designed to provide fluid communication between the branches of the external space, and fluid communication between the branches of the internal space; and a first fan positioned in at least one of the at least two openings and operable in the following two states: an open state allowing circulation of air between the external space and the internal space via at least one of the at least two openings to allow heat transfer between the panel and the wall; and a closed state preventing circulation of air between the external space and the internal space to prevent transfer of heat between the panel and the wall.
 2. Device according to claim 1, wherein the at least two openings are positioned substantially at a same distance from a lower edge of the wall of the device.
 3. Device according to claim 1, wherein one of the at least two openings is provided between a first branch of the external space and a first branch of the internal space, and another of the at least two openings is provided between a second branch of the external space and a second branch of the internal space.
 4. Device according to claim 1, wherein the first fan is an electric fan operable between on and off states, corresponding respectively to the open state and the closed state.
 5. Device according to claim 1, wherein the first fan is an electric fan, and a valve is situated in one of the at least two openings.
 6. Device according to claim 1, further comprising a supplementary plate positioned between the panel and the insulating plate to create a closed blocking space between the external space and the insulating plate.
 7. Device according to claim 1, further comprising an intermediate plate between the panel and the insulating plate creating a first air circuit to transfer heat between the intermediate plate and the wall, and a second air circuit to extract the heat towards an outside atmosphere, wherein the first fan drives the air in the first air circuit and a second fan drives the air in the second air circuit, and wherein the first and second fans are operable between on and off states, corresponding respectively to the open state and the closed state.
 8. Device according to claim 7, wherein the first air circuit is a closed circuit capable of communicating with the outside atmosphere through a small pressure balancing opening, and wherein the second air circuit is one of a closed circuit or is open to the atmosphere.
 9. Device according to claim 1, further comprising a controller to control the first fan.
 10. Device according to claim 9, wherein the controller is manually activated.
 11. Device according to claim 9, wherein the controller includes at least two temperature sensors designed to detect the temperatures of at least one of the panel, the intermediate plate, and the wall, in order to control the first fan as a function of differences in temperature.
 12. Device according to claim 9, wherein the controller is an automatic controller.
 13. Device according to one of claim 9, wherein the controller include at least one photo-responsive component to detect isolation on the panel and to generate a voltage representative of the isolation.
 14. Device according to claim 13, wherein the voltage generated by the photo-responsive component is used to power the first fan.
 15. Device according to claim 13, wherein the voltage generated by the photo-responsive component is used to form a signal to turn the first fan on or off.
 16. Device according to claim 1, wherein the device is a module including a frame. 